The Brussels sprout is a member of the Gemmifera Group of cabbages (Brassica oleracea), grown for its edible buds. The leafy green vegetables are typically 2.5–4 cm (0.98–1.6 in) in diameter and look like miniature cabbages. The Brussels sprout has long been popular in Brussels, Belgium, and may have originated and gained its name there.[1]

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Forerunners to modern Brussels sprouts were likely cultivated in ancient Rome. Brussels sprouts as they are now known were grown possibly as early as the 13th century in what is now Belgium.[2] The first written reference dates to 1587.[2] During the 16th century, they enjoyed a popularity in the southern Netherlands that eventually spread throughout the cooler parts of Northern Europe.

Brussels sprouts grow in temperature ranges of 7–24 °C (45–75 °F), with highest yields at 15–18 °C (59–64 °F).[3] Fields are ready for harvest 90 to 180 days after planting.[2] The edible sprouts grow like buds in helical patterns along the side of long, thick stalks of about 60 to 120 cm (24 to 47 in) in height, maturing over several weeks from the lower to the upper part of the stalk. Sprouts may be picked by hand into baskets, in which case several harvests are made of five to 15 sprouts at a time, or by cutting the entire stalk at once for processing, or by mechanical harvester, depending on variety.[2] Each stalk can produce 1.1 to 1.4 kg (2.4 to 3.1 lb), although the commercial yield is about 900 g (2.0 lb) per stalk.[3] Harvest season in temperate zones of the northern latitudes is September to March, making Brussels sprout a traditional winter stock vegetable. In the home garden, harvest can be delayed as quality does not suffer from freezing. Sprouts are considered to be sweetest after a frost.[4]

Most American production is in California,[7] with a smaller percentage of the crop grown in Skagit Valley, Washington, where cool springs, mild summers and rich soil abounds, and to a lesser degree on Long Island, New York.[9] Total American production is approximately 32,000 tons, with a value of $27 million.[3]

About 80% to 85% of US production is for the frozen food market, with the remainder for fresh consumption.[9] Once harvested, sprouts last three to five weeks under ideal near-freezing conditions before wilting and discolouring, and about half as long at refrigerator temperature.[3] American varieties are generally 2.5–5 cm (0.98–1.97 in) in diameter.[3]

Brussels sprouts and other brassicas are also a source of indole-3-carbinol, a chemical being studied for how it affects DNA repair in cells and appears to block the growth of cancer cells in vitro.[12][13]

Consuming Brussels sprouts in excess may not be suitable for heart patients taking anticoagulants since they contain vitamin K, a blood-clotting factor. In one such reported incident, doctors determined that the reason for a heart patient's worsening condition was eating too many Brussels sprouts which countered the intended effects of blood-thinning therapy.[14]

The most common method of preparing Brussels sprouts for cooking begins with cutting the buds off the stalk. Any surplus stem is cut away, and any loose surface leaves are peeled and discarded. Once cut and cleaned, the buds are typically cooked by boiling, steaming, stir frying, grilling, or roasting. To ensure even cooking throughout, buds of a similar size are usually chosen. Some cooks will make a single cut or a cross in the center of the stem to aid the penetration of heat. Brussels sprouts can be pickled as an alternative to cooking.

Overcooking will render the buds gray and soft, and they then develop a strong flavour and odour that some dislike.[7] The odour is associated with glucosinolate sinigrin, an organic compound that contains sulfur: hence the strong smell.

For taste, roasting Brussels sprouts is a common way to cook them in large quantities that seems to bring out the flavour that school children can enjoy.[15] One school district served roasted and pickled Brussels sprouts to 20,000 children who reportedly enjoyed the food during a single day.[16]